package com.xinjian.jianba.examples;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.Security;
import java.util.Date;

import javax.crypto.Cipher;  
import javax.crypto.spec.IvParameterSpec;  
import javax.crypto.spec.SecretKeySpec;

import com.sun.org.apache.regexp.internal.recompile;

import sun.misc.BASE64Decoder;  
import sun.misc.BASE64Encoder;  
  
public class AesEncodeUtil {  
  
    //偏移量
    public static final String VIPARA = "0392039203920300";   //AES 为16bytes. DES 为8bytes  
      
    //编码方式
    public static final String CODE_TYPE = "UTF-8";
//    public static final String CODE_TYPE = "GBK";
    
    //填充类型
    //public static final String AES_TYPE = "AES/ECB/PKCS5Padding";
    //public static final String AES_TYPE = "AES/ECB/PKCS7Padding";
    public static final String AES_TYPE = "AES/CBC/PKCS7Padding";
    //此类型 加密内容,密钥必须为16字节的倍数位,否则抛异常,需要字节补全再进行加密
//    public static final String AES_TYPE = "AES/ECB/NoPadding";
    //java 不支持ZeroPadding
    //public static final String AES_TYPE = "AES/CBC/ZeroPadding";
      
    //私钥  
    private static final String AES_KEY="sfl#dwi!acjjmkjb";   //AES固定格式为128/192/256 bits.即：16/24/32bytes。DES固定格式为128bits，即8bytes。  
    
    //字符补全
    private static final String[] consult = new String[]{"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F","G"};

    
    /** 
     * 加密 
     *  
     * @param cleartext 
     * @return 
     */  
    public static String encrypt(String cleartext) {  
        //加密方式： AES128(CBC/PKCS5Padding) + Base64, 私钥：1111222233334444  
        try {  
        	Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
            IvParameterSpec zeroIv = new IvParameterSpec(VIPARA.getBytes());  
            //两个参数，第一个为私钥字节数组， 第二个为加密方式 AES或者DES  
            SecretKeySpec key = new SecretKeySpec(AES_KEY.getBytes("utf-8"), "AES");
            //实例化加密类，参数为加密方式，要写全  
            Cipher cipher = Cipher.getInstance(AES_TYPE); //PKCS5Padding比PKCS7Padding效率高，PKCS7Padding可支持IOS加解密  
            //初始化，此方法可以采用三种方式，按加密算法要求来添加。（1）无第三个参数（2）第三个参数为SecureRandom random = new SecureRandom();中random对象，随机数。(AES不可采用这种方法)（3）采用此代码中的IVParameterSpec  
            //加密时使用:ENCRYPT_MODE;  解密时使用:DECRYPT_MODE;
            cipher.init(Cipher.ENCRYPT_MODE, key,zeroIv); //CBC类型的可以在第三个参数传递偏移量zeroIv,ECB没有偏移量
            //加密操作,返回加密后的字节数组，然后需要编码。主要编解码方式有Base64, HEX, UUE,7bit等等。此处看服务器需要什么编码方式 
            byte[] encryptedData = cipher.doFinal(cleartext.getBytes(CODE_TYPE));  
  
            return new BASE64Encoder().encode(encryptedData);  
        } catch (Exception e) {  
            e.printStackTrace();  
            return "";   
        }  
    }  
  
    /** 
     * 解密 
     *  
     * @param encrypted 
     * @return 
     */  
    public static String decrypt(String encrypted) {  
        try {  
        	Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
            byte[] byteMi = new BASE64Decoder().decodeBuffer(encrypted);  
        //	byte[] byteMi=hexStringToByte(encrypted);
            IvParameterSpec zeroIv = new IvParameterSpec(VIPARA.getBytes());  
            SecretKeySpec key = new SecretKeySpec(  
            		AES_KEY.getBytes("utf-8"), "AES");  
            Cipher cipher = Cipher.getInstance(AES_TYPE);  
            //与加密时不同MODE:Cipher.DECRYPT_MODE  
            cipher.init(Cipher.DECRYPT_MODE, key,zeroIv);  //CBC类型的可以在第三个参数传递偏移量zeroIv,ECB没有偏移量
            byte[] decryptedData = cipher.doFinal(byteMi);  
            return new String(decryptedData, CODE_TYPE);  
        } catch (Exception e) {  
            e.printStackTrace();  
            return "";  
        }  
    }  
  
    /** 
     * 测试 
     *  
     * @param args 
     * @throws Exception 
     */  
    public static void main(String[] args) throws Exception {  
        String content = "{\"infoIds\":[\"128a\"],\"groupId\":\"11B\",\"groupName\":\"群组\"}";
        System.out.println(content);
        String encryptStr=encrypt(content);
        System.out.println(encryptStr);
        System.out.println(1);
//        String decryptStr=decrypt("Y7mb+EJwjFBM7TCu9ejqAA==");
//        System.out.println(decryptStr);
    	System.out.println(new Date().getTime());
        
    }
    
    public static void test(String content) throws UnsupportedEncodingException{
    	System.out.println("加密内容：" + content);
    	//字节数
    	int num = content.getBytes(CODE_TYPE).length; 
        System.out.println("加密内容字节数: " + num);
        System.out.println("加密内容是否16倍数: " + (num%16 == 0 ? true : false));
      
        //字节补全
        if(AES_TYPE.equals("AES/ECB/NoPadding")){
        	System.out.println();
        	content = completionCodeFor16Bytes(content);
        	System.out.println("加密内容补全后: "+content);
        }
        
        System.out.println();
        
        // 加密
        String encryptResult = encrypt(content);  
        content = new String(encryptResult);
        System.out.println("加密后：" + content);
        
        System.out.println();
        
        // 解密
        String decryptResult = decrypt(encryptResult);
        content = new String(decryptResult);
        //还原
        if(AES_TYPE.equals("AES/ECB/NoPadding")){
        	System.out.println("解密内容还原前: "+content);
        	content = resumeCodeOf16Bytes(content);
        }
        
        System.out.println("解密完成后：" + content);  
    }
    
    
    
    
    //NoPadding 
    //补全字符
    public static String completionCodeFor16Bytes(String str) throws UnsupportedEncodingException{
    	int num = str.getBytes(CODE_TYPE).length;
    	int index = num%16;
    	//进行加密内容补全操作, 加密内容应该为 16字节的倍数, 当不足16*n字节是进行补全, 差一位时 补全16+1位
    	//补全字符 以 $ 开始,$后一位代表$后补全字符位数,之后全部以0进行补全;
    	if(index != 0){
    		StringBuffer sbBuffer = new StringBuffer(str);
    		if(16-index == 1){
    			sbBuffer.append("$" + consult[16-1] + addStr(16-1-1));
    		}else{
    			sbBuffer.append("$" + consult[16-index-1] + addStr(16-index-1-1));
    		}
    		str = sbBuffer.toString();
    	}
    	return str;
    }
    
    //追加字符
    public static String addStr(int num){
    	StringBuffer sbBuffer = new StringBuffer("");
    	for (int i = 0; i < num; i++) {
    		sbBuffer.append("0");
		}
    	return sbBuffer.toString();
    }
    
    
    //还原字符(进行字符判断)
    public static String resumeCodeOf16Bytes(String str){
    	int indexOf = str.lastIndexOf("$");
//    	System.out.println(indexOf);
    	if(indexOf == -1){
    		return str;
    	}
    	String trim = str.substring(indexOf+1,indexOf+2).trim();
//    	System.out.println(trim);
    	int num = 0;
    	for (int i = 0; i < consult.length; i++) {
    		if(trim.equals(consult[i])){
    			num = i;
    		}
		}
    	if(num == 0){
    		return str;
    	}
    	return str.substring(0,indexOf).trim();
    }
    public static byte[] hexStringToByte(String hex) {
        int len = (hex.length() / 2);
        byte[] result = new byte[len];
        char[] achar = hex.toCharArray();
        for (int i = 0; i < len; i++) {
            int pos = i * 2;
            result[i] = (byte) (toByte(achar[pos]) << 4 | toByte(achar[pos + 1]));
        }
        return result;
    }
 
    private static byte toByte(char c) {
        byte b = (byte) "0123456789abcdef".indexOf(c);
        return b;
    }

} 
